The invention is based on a vehicle brake system as defined hereinafter. German Offenlegungsschrift 37 06 663 discloses a vehicle brake system of this generic type. An electrically controllable switchover device that is embodied as a so-called 3/2-way magnetic valve is associated with a rear wheel brake pressure booster of this vehicle brake system. A 3/2-way magnetic valve of this kind has the disadvantages of technical complexity and of the engineering expense for not only two valve seats but two closing elements as well, that are coupled to one another and must be actuated by a common armature of an electromagnet.